Depends on which 14 bolt we are talking about, working on and what it came out of. Theres a 14Bolt 9.5" SF, 14 bolt 10.5" FF early, Mid and late design, 14 bolt FF AAM 11.5 and 14 bolt FF AAM 11.8. Main differences is housing or center section offset and pinion position being either high or low,pinion yoke mounting length, tube diameter and WMS measurements. Assuming the differential has the same WMS width, pinion height and offset and tube diameter you cut the spring perches off and the spring mounting plates off the original, tack weld brackets on new Diff and measure drive angle @ pre-sprung suspension heigth and centered housing in frame. When all looks good weld away. Be fore-warned though. If the backets are HSS, UHS, UHSLA steel they cannot be reused as heat from welding weakens them and will fail. New ones will have to be fabricated or bought. As far as lift kits are concerned once you modify rear suspensions its a hit and miss on whether they will work as most lift kits are designed around OEM Specs and would require some custom fab. work to make it work.
